Unable to maintain FC in new pool/SWG conversion

[Kjac081]

Hi folks, looking for some advice here. Pool is relatively new, plaster and filled on 7/17. 20,000 in ground with WetEdge Satin matrix plaster, DE filter, AquaPure 1400 SWG. Initially, startup with a Fusion chlorine system and converted to SWG last week. Since then, I am unable to get FC acceptable.
After conversion, I backwashed and cleaned filter grids, shocked pool, added phosphate remover. Over a couple days, chlorine slowly dropped to zero.

I have confirmed the cell cell is working by testing a sample at a return jet, and I see the bubbles when it’s active. Currently running 12hours a day at 80%. Below is my most recent test result.
FC- 0
TC- .14
CC- .14
PH- 7.5 (fluctuating, adding acid every couple days)
CH-227
TA-69 (just added 3# soda to get to 80)
CYA-69( just added 1.5# to get to 80)
Copper-.1
Iron-0
Phosphates-0
Salt- 3200

These numbers are from a local store that has an electronic analyzer, but I have confirmed the basics with my Taylor DPD test kit. This isn’t my first SWG pool, and these numbers all seem to be in range of where my last pool did ok.

Any advice?

 

[Catanzaro]

You will need to add enough liquid chlorine to SLAM the pool and test every few hours to make sure you are holding chlorine (first and foremost). Once you pass the OCLT (Overnight Test), then you can turn your cell back on. How many lbs. of chlorine does your cell produce in a 24 hour period? At what time does your pump run and what is the cell % set to?

Maybe you have algae and it is consuming your chlorine. Just because it is not visible, does not mean you do not have it, and this is assuming your SWG is working and producing chlorine.

 

[Jimrahbe]

k,

Welcome to TFP... a great place to find the answers to all of your "Out of my League pool questions"..

Assuming your cell puts out 1.4 lbs. of chlorine per day, when running at 100%, means that it should increase your FC by 8.4 ppm per day... Since you are running for 12 hours that would be 4.2 ppm and 80% of that is and increase of 3.3 ppm... Most pools use 2 to 4 ppm of chlorine a day, so 3.3 ppm may not be enough to maintain your FC level in Texas...

And now that you have allowed your FC to drop to zero, you could have an algae bloom consuming even more of your FC.

SWCG's take a long time to increase your FC, so you should use liquid chlorine and raise your FC to 6 ppm (what it needs to be for a CYA of 80)... [FC/CYA][/FC/CYA]

The very first thing I would do is run an Overnight Chlorine Loss Test (OCLT), just to make sure nothing is eating your FC... Here is how..Overnight Chlorine Loss Test

If you pass the OCLT then increase your output to 100% and run the pump for 16 hours a day. Once you see your FC starting to increase each day, you can then reduce the percentage or run time ..

It is way easier to generate too much FC and reduce it, then it is to generate too little and try to increase it.

Thanks,

Jim R.

 

[Kjac081]

So you are are suggesting SLAMing it first to bring up the FC then do the overnight test? Repeating SLAM until I pass the overnight test too? I will have to search SLAM method, unless you have a link.

Why wouldnt shock kill off any algae in the water?

- - - Updated - - -

You will need to add enough liquid chlorine to SLAM the pool and test every few hours to make sure you are holding chlorine (first and foremost). Once you pass the OCLT (Overnight Test), then you can turn your cell back on. How many lbs. of chlorine does your cell produce in a 24 hour period? At what time does your pump run and what is the cell % set to?

Maybe you have algae and it is consuming your chlorine. Just because it is not visible, does not mean you do not have it, and this is assuming your SWG is working and producing chlorine.

I have my run times split into two sessions; 6am-2pm, and 7pm-11pm. I do this to avoid peak energy rates. You think splitting up the run time could affect it?

 

[mknauss]

SLAM Process is a process. You raise your FC to shock level based on CYA - [FC/CYA][/FC/CYA]. You then maintain that FC, testing FC and adding liquid chlorine, until you are able to pass a Overnight Chlorine Loss Test, have a CC of 0.5 or less, and have crystal clear water.

 

[Catanzaro]

I have my run times split into two sessions; 6am-2pm, and 7pm-11pm. I do this to avoid peak energy rates. You think splitting up the run time could affect it?

This pump run time is fine once the SLAM is complete. During the SLAM process, the pump will need to run 24/7 until you pass the OCLT.

 

[Jimrahbe]

K,

Unless you have visible algae, then you should do an OCLT first... If you pass the OCLT then you do not need to do a SLAM.

If you have visible algae, then there is no reason to do an OCLT... You should then move on to doing a SLAM.. here is how...SLAM Process

At the end of a SLAM, you do an OCLT to verify that you have passed at least that part of the SLAM.

Thanks,

Jim R.

 

[Kjac081]

Thanks for for all the help, and sorry for the questions that probably seem obvious to you all.

So, the OCLT test procedure I read said to maintain FC at 3.0 before starting OCLT, but I can’t get there without shocking. Should I use shock or liquid chlorine to get it there, and then follow the OCLT?

K,

Unless you have visible algae, then you should do an OCLT first... If you pass the OCLT then you do not need to do a SLAM.

If you have visible algae, then there is no reason to do an OCLT... You should then move on to doing a SLAM.. here is how...SLAM Process

At the end of a SLAM, you do an OCLT to verify that you have passed at least that part of the SLAM.

Thanks,

Jim R.

 

[Kjac081]

So I read the SLAM. Basically, it is shocking the pool and continuous chlorine additions to maintain shock level FC for a long time (1 day?). When I shocked my pool last week, CYA was around 70, and I used two bags of shock. Since I don’t have a FAS test kit, I don’t know if I got the FC to the correct shock level.

 

[mknauss]

If you need to SLAM, it can take days to a couple weeks. You use liquid chlorine. With a CYA of 70, the shock level is 28 ppm FC.

You must have a FAS-DPD test to properly do a OCLT or SLAM.

Order one now -- FAS/DPD Chlorine CC's test

 

[Kjac081]

No algae visible at all. Now that I have read more about slamming, I don’t want to unless I have to, but suspect I may need to since the pool has essentially never been properly shocked since start up with city water. The fusion tablet dispenser never really maintained levels either come to think about it.

So, I got the Pool math app, and it says I need 9 gallons bleach at 6% to hit my target shock FC level. I don’t see any way around doing this at least once in order to facilitate the overnight test.

In a nutshell, if I get FC up over 3.0 before night, and in the morning the level has dropped (per test process) I need to do a full slam?

K,

Unless you have visible algae, then you should do an OCLT first... If you pass the OCLT then you do not need to do a SLAM.

If you have visible algae, then there is no reason to do an OCLT... You should then move on to doing a SLAM.. here is how...SLAM Process

At the end of a SLAM, you do an OCLT to verify that you have passed at least that part of the SLAM.

Thanks,

Jim R.

 

[mknauss]

To properly do a OCLT you need to bring your FC up to at least 6 or 8 ppm. Then you need a FAS-DPD test to accurately test your FC. The color match tests are not accurate enough.

If your FC drops by more than 1 ppm over night or your CC is greater than 0.5 ppm, you need to SLAM

 

[Kjac081]

Got it. Thanks. Will order a kit and try it. I guess I probably still need bleach just to get the level up to 6-8 for the test.

Is is there any benefit to going ahead will one initial shock, done at night to serve as the test? I was told that to get a SWG system running, the pool has to be shocked initially past the break even point, and I never did that.

To properly do a OCLT you need to bring your FC up to at least 6 or 8 ppm. Then you need a FAS-DPD test to accurately test your FC. The color match tests are not accurate enough.

If your FC drops by more than 1 ppm over night or your CC is greater than 0.5 ppm, you need to SLAM

 

[mknauss]

No such thing as a one time shock or break even point. Those are pool store statements. They are meaningless.

You do need to raise your FC to target level and then start your SWCG generating about 3 or 4 ppm per day and then adjust as necessary to maintain your FC in target level.

You can add liquid chlorine to raise your FC up to the limit your test will test. Problem is the error of the color matching tests is greater than the 1 ppm needed for a OCLT,

 

[Kjac081]

I definitely plan on getting a FAS kit, shopping now online. Will probably just get the Tf100, looks the same as the 2006c but cheaper.

Interesting comment about breakeven terminology; I always took it as the level of FC to superchlorinate and eliminate CC. Seems this is the goal regardless.

With my last pool, I only shocked it twice in 6 years; once at startup and another when a baby swim diaper malfunctioned. It never had CC and maintained FC good. I’m sure this is just startup woes and once I get it going, it should be easier to maintain.
Thanks again for the help. I’ll check back in after I get a better test kit.

No such thing as a one time shock or break even point. Those are pool store statements. They are meaningless.

You do need to raise your FC to target level and then start your SWCG generating about 3 or 4 ppm per day and then adjust as necessary to maintain your FC in target level.

You can add liquid chlorine to raise your FC up to the limit your test will test. Problem is the error of the color matching tests is greater than the 1 ppm needed for a OCLT,

 

[jimmythegreek]

If i were u I would grab a dozen bottles to start 10% liquid chlorine from a nearby big box. Dump 4 bottles in slowly to start off in morning and add 1 in afternoon and one in evening. Next morn add 1 in morn 1 in afternoon 1 in evening and do the same the third day until ur test kit arrives. Run ur pump 24 7 for all of it and if bet u get good #s when kit arrives. After 3rd day go back to ur reg pump sched and put swg to 100% til u can test w tft kit.

When we say pool store tests are unreliable it's very true. I am a lazy tester but I kno my pools behavior now. I took my water several times to Leslie's and another local place and they were way off each time. The pool places say to shock once a week and add this and that but it's mainly to sell u product they rly don't have a clue. Even pool services can be bad I tested my cousins water this season who pays big money for the install company to maintain his chemistry and it was rly off. They basically ruined his high end liner in 6yrs cause of chem unbalance

 

[Kjac081]

Well, I didn’t do that exactly. I did add 7 gallons of 8.25% HDX brand last night. Based on pool math, should have gotten me to 28ppm. Will crank up the SWG and run more like you suggested for a few days and see what happens. Maybe one shock was enough to kill off anything, but I will have to waist for my FAS DPD test in a few days to really start the troubleshooting.

If i were u I would grab a dozen bottles to start 10% liquid chlorine from a nearby big box. Dump 4 bottles in slowly to start off in morning and add 1 in afternoon and one in evening. Next morn add 1 in morn 1 in afternoon 1 in evening and do the same the third day until ur test kit arrives. Run ur pump 24 7 for all of it and if bet u get good #s when kit arrives. After 3rd day go back to ur reg pump sched and put swg to 100% til u can test w tft kit.

When we say pool store tests are unreliable it's very true. I am a lazy tester but I kno my pools behavior now. I took my water several times to Leslie's and another local place and they were way off each time. The pool places say to shock once a week and add this and that but it's mainly to sell u product they rly don't have a clue. Even pool services can be bad I tested my cousins water this season who pays big money for the install company to maintain his chemistry and it was rly off. They basically ruined his high end liner in 6yrs cause of chem unbalance

 

[Kjac081]

So on Saturday, I added enough bleach to get to the calculated shock level per pool math. Since then, I got probably 6” of rain and a portion of run time without AquaPure working due to pool company rewiring.

I got my FAS test kit yesterday and FC was at 3.5 and CC at .5 at 5pm. I noticed my AquaPure was set to 0% since they had come out and connected it to the AquaLink controller. I turned it back up to 80% and got another 4 hours run time.

This morning at 5am, FC was at 5.0, CC was 0. This tells me the system is working now, and next step is to to a complete overnight test once I get my FC up to target level.